1. Field
The present inventive concept relates to a signal processing method of transmitting and receiving a spatial parameter, and an encoding and decoding apparatus. More particularly, the inventive concept relates to a signal processing method of transmitting and receiving a spatial parameter used to encode a stereo signal to a mono signal and to restore the mono signal to the stereo signal.
2. Description of the Related Art
An encoding and decoding apparatus for multi-channel input and output, encode and decode an audio signal including voice, music, or the like by using a predetermined codec, and transceive a decoded signal. With respect to an audio codec, if there is one input/output channel, it is referred to as a mono-channel, and if there are two input/output channels, they are referred to as stereo channels. A representative example of audio coding for processing a stereo signal includes parametric stereo coding.
According to the parametric stereo coding, stereo signals which correspond to two channels are received and down-mixed, so that a mono signal is generated. Then, a down-mixed mono signal is encoded and transmitted to a decoding apparatus, or the like. An encoding apparatus generates a predetermined parameter used to restore the down-mixed mono signal to the original stereo signals, encodes the predetermined parameter, includes the encoded predetermined parameter and the encoded mono signal in a transport stream, and then transmits them to the decoding apparatus.
Here, the predetermined parameter may indicate a spatial parameter. Also, in a case where the original stereo signals are divided into a plurality of sub-frequency bands and then are encoded, the spatial parameter is transmitted from each of the plurality of sub-frequency bands.
In order to allow the mono signal to be restored exactly to the original stereo signals, there is an increase in an amount of data of the spatial parameter. This is because the spatial parameter has to include detailed information regarding the original stereo signals, and detailed information regarding a correlation between the original stereo signals and the mono signal.
However, data exchange between the encoding apparatus and the decoding apparatus is performed using limited bandwidth, so that, when the amount of data of the spatial parameter is increased, the efficiency of use of the bandwidth deteriorates, and a speed of the data exchange between the encoding apparatus and the decoding apparatus is decreased.
Also, if the amount of data of the spatial parameter is decreased in order to increase the use efficiency of the bandwidth and the speed of the data exchange, the mono signal may not be restored exactly to the original stereo signal.
Thus, there is a requirement to provide a method and apparatus for increasing the efficiency of use of the bandwidth and the speed of data exchange, without deteriorating the exactness of the restoration.